1. Technical Field
The present disclosure relates generally to the field of wireless devices. More particularly, in one exemplary embodiment, the present disclosure is directed to controlling parameters such as the transmit power of a wireless device.
2. Description of Related Technology
Modern wireless devices such as smartphones and tablet computers are highly sophisticated devices which may employ many different air interfaces; e.g., cellular (such as LTE, CDMA, GSM, etc.), WLAN (e.g., Wi-Fi), PAN (e.g., Bluetooth), as well as other complex functions such as media streaming, multi-touch display and input devices, speech recognition, etc. Some of these functions can be location-specific in nature, such that certain limitations, rules, restrictions, or modes must be employed in certain geographic areas.
For example, in the specific case of radio frequency (RF) transmitters, such transmitters are regulated by local regulatory domains to ensure efficient use of wireless spectra, and to control the level of interference any one wireless application creates for other applications. These regulatory domains may include a part of a country or state or territory, a single country, or may even include multiple countries. Two major tools for implementing such regulations are (i) licensing, and (ii) limiting unlicensed use of wireless spectra. For licensed usage, a regulatory domain provides specific limits for the license holder that may detail every aspect of transmission (e.g. allowed power, frequency, channel number, channel spacing, channel hopping rate/sequence, power spectrum, digital/analog transmission, coding scheme, etc.). For unlicensed usage, regulatory domains provide general guidelines that apply to all users. Generally, specific frequency bands are set aside for unlicensed use. Although in many cases any user may use such bands freely, limits (e.g. maximum allowed power, allowed channels, etc.) are set forth to mitigate effects of activity by any one user on the activity of another.
The aforementioned limitations may change from one regulatory domain to another. In some cases, the frequency bands reserved for unlicensed usage may change from one regulatory domain to another. Further, even if the reserved unlicensed usage frequency remains constant from one regulatory domain to another, the particular limitations (such as the maximum transmit power or spectral masks allowed) may still change. Licensed usage is specifically controlled by each regulatory domain, and consequently, limitations associated with licensed wireless usage may also change between regulatory domains. As used herein, the term “spectral mask” (also known as a “channel mask” or “transmission mask”) refers to a mathematically-defined mask that defines transmission power as a function of frequency (or increment thereof).
To avoid violating these regulations, wireless manufacturers wishing to create devices complaint with all or multiple regulatory domains must design their devices to comply with the strictest regulations of any of the domains in question. For example, in a group of ten regulatory domains, a first one may limit power transmitted by a device to a level that is 3 dB lower than the other nine. In this case, a device compliant with all ten regulatory domains would transmit at a power 3 dB lower than required in nine of those regulatory domains. In this same example, if a second one of the ten domains limits channel usage to two channels where the other nine allow three channels, compliance with all domains would require more strict regulations than would be present in any one of the ten domains.
Situations of conflicting regulations between two regulatory domains may also result. In these situations, it may be impossible to create a device compliant with both domains simultaneously. Accordingly, vendors create hardware that may only comply with a single regulatory domain (or a limited number). Consumers, transporting this domain-specific hardware to regions where it is non-compliant may be unaware they are violating local regulations. Further, they may unwittingly interfere with local legal spectrum usage. In addition, end-users may experience lower product satisfaction if they find that hardware purchased across multiple domains is not interoperable (or mistakenly identified as completely inoperable). Consequently, manufacturers are also required to make multiple versions of the same device (or related devices) to participate in global markets. This may lead to increased product overhead.
Hence, the current use of fixed methods of multiple regulatory domain compliance are inefficient, and, inter alia, do not take full advantage of permitted spectrum usage in all regulatory domains. Ideally, a device would be capable of selective control of its parameters (such as those relating to spectral emissions) and universal regulatory compliance, without need to meet the limitations from all domains simultaneously.